1. Field of the Invention
The present general inventive concept relates to a switching power amplifier, and more particularly, to a switching power amplifier that removes non-linearity of a power amplification unit by converting an input audio signal into a pulse width modulation (PWM) signal, removing a carrier frequency from a the PWM signal, and modulating the PWM signal so that the PWM signal has a new frequency for operation of a power stage.
2. Description of the Related Art
Class-A power amplifiers, class-B power amplifiers, and class-AB power amplifiers are generally used as linear analog power amplifiers. These linear analog power amplifiers have good linearity but provide low efficiency, thus resulting in large power loss. To address this problem, switching power amplifiers (also referred to as class-D power amplifiers) providing high efficiency have been proposed. These switching power amplifiers basically change an input signal into a pulse width modulation (PWM) signal, and amplify the input signal using a power switch stage. However, the performance of switching power amplifiers may be degraded due to the non-linearity of the power switch stage. The non-linearity of the power switch stage degrades the total harmonic distortion (THD) and generates out of band noise, thereby degrading the signal-to-noise ratio (SNR). In addition, noise is generated in an output signal due to the non-linearity and ripple of the power unit connected to the power switch stage of the switching power amplifiers.